1. Field of the Invention
The present invention relates to a thin film magnetic head having at least an inductive magnetic transducer for recording, a method of manufacturing the same, and a magnetic recording apparatus on which the thin film magnetic head is mounted
2. Description of the Related Art
In recent years, in association with improvement in areal density of a magnetic recording medium (hereinbelow, simply called “recording medium”) such as a hard disk, improvement in performance of a thin film magnetic head to be mounted on a magnetic recording apparatus such as a hard disk drive is demanded. There is a widely used thin film magnetic head, in general, having a reproduction head portion which includes a magneto-resistive (MR) effect element as a magnetic transducer for reproducing and a recording head portion which includes an inductive magnetic transducer for recording, and having a structure in which the reproduction head portion and the recording head portion are stacked. A thin film magnetic head of this kind is called a “composite thin film magnetic head”.
The reproduction head portion having a magnetic reproduction function in the composite thin film magnetic head includes, mainly, an MR element, a lower read shield layer and an upper read shield layer which are disposed so as to face each other by sandwiching the MR element. On the other hand, the recording head portion having a magnetic recording function mainly includes: a lower magnetic layer and an upper magnetic layer which face each other via a recording gap layer on the side close to a recording medium facing surface (air bearing surface) that faces a recording medium and are magnetically coupled to each other through a back gap on the side far from the air bearing surface, thereby forming a ring-shaped magnetic path as a whole; and a thin film coil which spirally winds so as to pass through a space surrounded by the lower and upper magnetic layers and generates a magnetic flux for recording. Particularly, the lower magnetic layer, the recording gap layer and the upper magnetic layer have the same width on the side close to the air bearing surface and form a so-called trim structure.
In the composite thin film magnetic head, when a magnetic flux for recording generated by the thin film coil is received by the upper and lower magnetic layers, a magnetic field for recording (recording magnetic field) is generated on the basis of the magnetic flux leaked near the recording gap layer. Therefore, a recording medium is magnetized along its surface by the recording magnetic field. As a result, information is magnetically recorded onto the recording medium. The ring-shaped magnetic path structure formed by the upper and lower magnetic layers is called a “ring head” and a recording method in which the recording medium is magnetized along its surface by using the ring head is called a “longitudinal recording method”. On the other hand, the magnetic path structure which extends in a direction orthogonal to the recording medium is called a “single-magnetic-pole head” and a recording method in which the recording medium is magnetized in a direction orthogonal to its surface by using the single-magnetic-pole head is called a “perpendicular recording method”.
In processes of developing a thin film magnetic head, in order to improve recording performance, various techniques have already been proposed with respect to the configuration of the thin film magnetic head.
Concretely, with respect to the configuration of a thin film magnetic head in the perpendicular recording method, there is a known technique of constructing a single-magnetic-pole head so as to have a stacked structure in which a nonmagnetic layer formed of a specific nonmagnetic metal and a magnetic layer formed of iron (Fe) and cobalt (Co) are stacked in order to prevent recorded data from being unintentionally erased by a leaked magnetic field (for example, refer to Japanese Patent Laid-open No. 2005-025890).
There is also a known technique in which ruthenium (Ru) is deposited as a base layer and, after that, iron cobalt alloy (Fe70CO30) as a soft magnetic material is deposited on the base layer to improve soft magnetic properties of the magnetic materials applied to the thin film magnetic head (refer to, for example, Non-Patent Document 1: Journal of The Magnetics Society of Japan, Vol. 28, No. 9, pp. 963 to 968, 2004.